Hypertonic saline during CPR: Feasibility and safety of a new protocol of fluid management during resuscitation.

BACKGROUND AND PURPOSE: In experimental studies infusion of hypertonic saline during cardiopulmonary resuscitation (CPR) increased resuscitation success rate and improved myocardial and cerebral reperfusion during CPR. We tested the feasibility and the safety of this new therapeutic measure in a randomised, preclinical pilot study. METHODS: The study was performed in the EMS system of Bonn after approval of the local ethical committee. Study inclusion criteria were out-of-hospital cardiac arrest (CA) of non-traumatic origin, age > or =18 years, application of adrenaline (epinephrine) during CPR, duration of CA < or = 15 min, and estimated body weight < or = 125 kg. Patients randomly received 2 ml/kg/10 min HHS (7.2% NaCl with 6% hydroxy ethyl starch 200,000/0.5 [HES]) or HES alone. Haemoglobin, blood gases, plasma sodium and potassium concentrations were measured before and 10 min after infusion, and after admission to hospital. Feasibility and safety of the new fluid management was evaluated by looking for side effects and determination of resuscitation success and admission rates. RESULTS: Sixty-six patients were included. After infusion of HHS, plasma sodium concentration increased to 168+/-29 mmol/l at 10 min after application but already decreased to near normal (147+/-5.5 mmol/l) at admission to hospital. Patients receiving HHS showed a trend to higher resuscitation success and hospital admission rates (ROSC: HHS 66.7%, HES 51.5%, p = 0.21; admission: HHS 57.6%, HES 39.4%, p = 0.14). The benefit of HHS was more pronounced if duration of untreated CA was >6 min or if initial rhythm was asystole or pulseless electrical activity (PEA). Negative side-effects were not observed after HHS. CONCLUSIONS: HHS after CA is feasible and safe and might improve short term survival after CPR. However, whether giving HHS could be a useful measure to increase resuscitation success after out-of-hospital CA requires a larger preclinical trial.

Hypertonic saline improves myocardial blood flow during CPR, but is not enhanced further by the addition of hydroxy ethyl starch.

OBJECTIVE: To evaluate the effects of hypertonic saline (HS) and/or hydroxy ethyl starch (HES) on myocardial perfusion pressure (MPP) and blood flow (MBF), and cardiac index (CI) during and after cardiopulmonary resuscitation (CPR). METHODS: In 32 domestic swine (13-23.5 kg) open chest CPR was initiated after 8 min of ventricular fibrillation. With the onset of CPR animals randomly received 2 ml/kg per 10 min of either HS (7.2% NaCl) or hypertonic HES saline (HHS) (6% HES 200000/0.5 in 7.2% NaCl) or HES (6% HES 200000/0.5 in 0.9% NaCl) or normal saline (NS) (0.9% NaCl). Haemodynamic variables were monitored continuously, and coloured microspheres were used to measure MBF and CI before cardiac arrest, during CPR, and 20, 90 and 240 min after restoration of spontaneous circulation. RESULTS: During CPR HS and HHS significantly increased MBF in comparison to HES and NS (P<0.05, respectively, MANOVA). MPP and CI were not different between the groups. HS and HHS significantly increased resuscitation success and the 240 min survival rate. 14/15 animals receiving HS or HHS and 8/17 after HES-or NS -infusion survived the observation period (P<0.05, chi(2)-test). No negative side effects of HS with or without the addition of HES were observed. CONCLUSIONS: Hypertonic solutions (HS and HHS) applied during internal cardiac massage enhanced MBF and significantly increased resuscitation success and survival rate. Addition of HES to HS did not further improve the positive haemodynamic effects of HS alone.

Effects of hypertonic saline on myocardial blood flow in a porcine model of prolonged cardiac arrest.

OBJECTIVE: To evaluate the effects of hypertonic saline (HS) on myocardial reperfusion pressure (MPP) and blood flow (MBF), and cardiac index (CI) during and after cardiopulmonary resuscitation (CPR). METHODS: In 21 domestic swine (16-23 kg) open chest cardiac massage was initiated after 10 min of ventricular fibrillation. With the onset of CPR animals randomly received HS (7.2%; 2 ml/kg per 10 min or 4 ml/kg per 20 min) or normal saline ((NS); 2 ml/kg per 10 min). Haemodynamic variables were monitored continuously, and coloured microspheres were used to measure MBF and CI before cardiac arrest (CA), during CPR and 5, 30 and 120 min after the return of spontaneous circulation. RESULTS: During CPR HS significantly increased MPP, MBF, and CI in comparison to NS (P<0.05, resp., MANOVA). Doubling the volume of HS did not improve the haemodynamic effects seen after application of 2 ml/kg per 10 min. HS-infusion significantly increased the survival rate at 120 min, 6/7 and 5/7 animals receiving 2 ml/kg per 10 min or 4 ml/kg per 20 min versus 2/7 after NS-infusion (P<0.05, chi(2)-test). CONCLUSIONS: HS applied during open chest cardiac massage enhanced MBF and CI, and significantly increased resuscitation success and survival rate. The positive effects of this promising new approach need to be confirmed in clinical studies.